Feeding the tummies, gas tanks, and livestock of an ever-growing world population is coming at the expense of the world's tropical forests. This is the conclusion of a recent study by researchers at Stanford who found that 80 percent of new cropland developed between 1980 and 2000 in the tropics—half a million square miles—came from cutting down tropical forests.

Such deforestation sends carbon into the atmosphere, and lots of it. "The tropical forests store more than 340 billion tons of carbon, which is 40 times the total current worldwide annual fossil fuel emissions,” says Holly Gibbs, the study’s lead researcher.“If we continue cutting down these forests, there is a huge potential to further contribute to climate change."

Researchers are encouraged that in recent years much of this land was cleared by corporate agribusiness rather than small, individual farmers.Agribusiness has been more responsive to the global market and consumer demands, reducing farmland expansion and instead boosting production on lands already in agricultural use.

Crop yields have since increased, and the density of cattle grazing has been upped 5 or 6 fold in some areas. Such improved land use practices offer greater resource efficiency, said Gibbs, as well as hope for the future of sustainable farming.